【从零开始的Swift开发心路历程-Day23】天气预报App实作Part2

昨天我们已经能成功将JSON格式的资料print出来了，接着就来实作天气预报App吧！
首先，我们要先将JSON格式的资料写成Codable的Struct，这部分要细心一点不能出错！
我们要先新增一个.swift档

如这张图所示，JSON格式是层层包住的

那你.swift档里面的struct就必须这样写

struct Weather: Codable {
    var records: records
}

struct records: Codable {
    var location: [location]
}

struct location: Codable {
    var locationName: String
    var weatherElement: [weatherElement]
}

struct weatherElement: Codable {
    var elementName: String
    var time: [time]
}

struct time: Codable {
    var startTime: String
    var endTime: String
}

以此类推....
完成之後呢，我们上中央气象局的API说明文件来查看有什麽预报因子是我们所需要在App上显示出来的

分别是Wx天气现象,ManT最高温度,MinT最低温度,CI舒适度,PoP降雨机率，再将这些预报因子用UILabel来显示
然後要写一个function来解析JSON资料

func loadAPI(locationName: String ,time: Int){
        let url =  "https://opendata.cwb.gov.tw/api/v1/rest/datastore/F-C0032-001?Authorization=CWB-FCD3F473-1F08-455C-9FF0-11AE228B011E&format=JSON&locationName=\(locationName)&time=\(time)"
        let newUrl = url.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed)!
        var request = URLRequest(url: URL(string: newUrl)!,timeoutInterval: Double.infinity)
        request.httpMethod = "GET"
        let task = URLSession.shared.dataTask(with: request) { data, response, error in
            let decoder = JSONDecoder()
            if let data = data, let weather = try? decoder.decode(Weather.self, from: data){
                print(weather)
                DispatchQueue.main.sync {
                    self.locationName.text = weather.records.location[0].locationName
                    self.maxT.text = weather.records.location[0].weatherElement[4].time[0].parameter.parameterName + "°" + weather.records.location[0].weatherElement[4].time[time].parameter.parameterUnit!
                    self.minT.text = weather.records.location[0].weatherElement[2].time[0].parameter.parameterName + "°" + weather.records.location[0].weatherElement[2].time[time].parameter.parameterUnit!
                    self.cI.text = weather.records.location[0].weatherElement[3].time[time].parameter.parameterName
                    self.poP.text = weather.records.location[0].weatherElement[1].time[time].parameter.parameterName + "%"
                    self.startTime.text = weather.records.location[0].weatherElement[0].time[time].startTime
                    self.endTime.text = weather.records.location[0].weatherElement[0].time[time].endTime
                    self.wx.text = weather.records.location[0].weatherElement[0].time[time].parameter.parameterName
                }
            }
            else {
                print("error")
            }
        }
        task.resume()
    }

之後按执行

就能成功在App上显示天气资讯啦！
但现在只能显示台中市的天气资讯
明天我们就来利用UIButton来选择想要的地点及时间